November 23, 2004

Tagging kids, revisited

Do I really care which kid leaves? I just want kids to leave only with permission. What I want is not RFID but electronic article surveillance (EAS).

Three types of EAS systems dominate the retail industry. In each case, an EAS tag or label is attached to an item. The tag is then deactivated, or taken from an active state where it will alarm an EAS system to an inactive state where it will not flag the alarm. If the tag is a hard, reusable tag, a detacher is used to remove it when a customer purchases the item it's attached to. If it's a disposable, paper tag, it can be deactivated by swiping it over a pad or with a handheld scanner that "tells" the tag it's been authorized to leave the store. If the item has not been deactivated or detached by the clerk, when it is carried through the gates, an alarm will sound.

It looks like the detectors cost about $1000-$2000. Labels are cheap, 2000 for about $100. The labels are deactivated using a "detuner" which costs about $300. Now the question is, is it ok for the kid to stand next to the deactivator for too long?

Ahh, here's a good activate/reactivate system. Used widely in Europe, the electromagnetic (EM) system relies on a magnetic, iron-containing strip.

What most people refer to as an electromagnetic tag is actually a metal wire or ribbon that has high permeability, making it easy for magnetic signals to flow through it, according to Sensormatic's EAS Product Co. CTO Hap Patterson. "When we drive the tag, flux is being allowed to flow through the tag until it's saturated," he says. "When it's saturated, from a magnetic perspective, it begins to look like air. Saturation occurs abruptly and is an important part of the design of the tag."
So, activate the kid when they come in, and deactivate them on the way out. Here's another view from "tagcompany".

Posted by torque at 4:58 PM | Comments (0) | TrackBack

RFID bracelets for kids, continued

The RFID tags I'm interested in do not have to have many bits. An 8-bit system is probably sufficient. RFID's in the market today have substantially more information as they are used to tag huge numbers of objects. What I do want is a thin, passive RFID tag which has a range of about 1 m. The goal is to have some sort of doorway, which will trigger an alarm if a child leaves without proper (parental) authorization. Oh, and the tags don't have to be writeable, read-only is good enough.

Here's an interesting thread.

Posted by torque at 4:38 PM | Comments (0) | TrackBack

RFID bracelets for kids

I'm interested in an RFID check-in and check-out system for kids. I guess it really doesn't have to be RFID in the digital sense of the word. It would work much like a library. Bar-code bracelets might work too, but it would be nice to do the transaction remotely. There's an interesting article on RFID at Kindercity in Switzerland. This system is used to charge the kids' debit account when visiting particular attractions.

Synometrix sells some "low cost disposable RFID bracelets" which have a reading distance of 8 cm. An article in June 2004 describes RFID at Legoland.

Children entering the parks will be fitted with an RFID bracelet that can be tracked anywhere within its boundaries - meaning that should they run off and find themselves lost, the parks' staff will easily be able to track them down and alert parents via SMS.
I wonder if the kids are tracked at each location or if the range is large enough that they can have some large towers handling the detection process. The company which does this is called kidspotter. Ahh, here it is. Sounds expensive!
KidSpotter T2 tags. These sturdy, waterproof tags measure just 62mm x 40mm and include a variety of functional mounting options such as wristband attachment and a badge clip. Each tag unit has a unique identifier that is the MAC address of the 802.11b radio, allowing the software to recognize an individual tag. The tag is the only long-life Wi-Fi tag on the market, with a battery life of 3 years and a weight of just 35 grams.
More details are available in Jonathan Collins' in-depth article on the whole system. In fact, the core system was developed by Bluesoft. Cost? List price is $85 per tag. Legoland has 500 and plans to buy thousands more. Receivers cost between $3000 and $4000 each. There are 38 in Legoland covering approximately 2.5 million square feet. Not bad. Tags last for about 3 years and are rented by parents for 3 euros per day. Still, a bit expensive for the church nursery.

Posted by torque at 4:15 PM | Comments (3) | TrackBack

May 10, 2004

MIT Club of Northern California hosts RFID panel

Thanks Christine, for sending me the link. Tomorrow MIT CLub of Northern California will be hosting an RFID panel 7:00 PM at Cooley Godward, LLP (Palo Alto, CA). Tickets are $15 pre-registration and $20 at the door. Note that the Register Now button appears to not be functioning at the moment.

Expected panelists:
Blair LaCorte, EVP, Corporate Development and Strategy, Savi Technology
Anurag Mendhekar, CEO, Blue Vector Systems
Jon Chorley, Senior Director, Oracle Inventory & WMS, Oracle Corporation
Raymond Blanchard, President & CEO, Truth Software. Former Business Development Director, Auto-ID Solutions, BSG Manufacturing, SAP

Peter Winer, CEO, Big Chief Partners, Inc.

Bios are available at the event description. Contact for more information.

Posted by torque at 11:37 AM | Comments (0) | TrackBack

May 5, 2004

RFID Academy

For a mere $5,000, you can attend Alien Technologies' RFID Academy where you'll get "years of RFID packed into two days". Included in the course is a choice of either a 915MHz Passive Development Kit and Circular Polarized Antenna OR a 2450MHz Long Range Battery Tag w/Temperature Data Logging Option. Woo woo! Sessions begin at 8:00 a.m. and end at 5:30 p.m., continental breakfast, snacks and buffet lunch provided. Alien is located in Morgan Hill, CA, 25 miles southeast of San Jose. I wonder if they offer student discounts.

Posted by torque at 10:20 PM | Comments (1) | TrackBack

April 30, 2004

Wal-mart's RFID revolution begins

Wal-mart, along with a number of their suppliers, began using RFID today at a Dallas distribution center. At the moment the tags are by the case and pallet though the end goal is to have the tags on individual items.

Partcipants (per

Now, who is their (RFID) supplier?

Posted by torque at 11:25 AM | Comments (0) | TrackBack

April 20, 2004

RFID file and book tracking

As is the case with most things that Ken and I come up with, it's done. Oh well, maybe we can focus on implementation.

On a more humorous note, read this and then this and then this. Yikes.

Posted by torque at 4:59 PM | Comments (0) | TrackBack


MIT's 6.033 had a design project last year on RFID that provides some good background on the technology. Among the interesting links is one on the FDA-approved VeriChip - a rice-sized RFID designed to be injected into humans. Actually, they weren't really approved, it was more that the FDA gave "written guidance" that the chip not be considered a "regulated medical device". It's actually kind of large, about the length of a dime (big piece of rice).

Posted by torque at 4:54 PM | Comments (0) | TrackBack